1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to downlink channel aggregation in high-speed wireless networks.
2. Background
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSDPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
In HSDPA multipoint (MP) transmission (TX), the data stream is split for two cells to transmit. In intra-NodeB MP TX, a single Medium Access Control (MAC) entity is shared by the two cells, and thus the split can occur at the MAC layer. However, in inter-NodeB MP TX, the MAC entity at each NodeB is separate. When implementing the split in the data steam at the Radio Link Control (RLC) layer, then data packets can result in out-of-order delivery, or skew, between the two MAC entities on a downlink to user equipment (UE). UE has incomplete knowledge about the transmission in that skew cannot be readily distinguished from data loss.